cmake: Fix typo in PackageConfig.

cmake/macros/PackageConfig.cmake

@@ -128,7 +128,7 @@ macro(target_use_packages target)
   foreach(lib ${libs})
     if(HAVE_${lib})
       target_include_directories("${target}" PUBLIC "${${lib}_INCLUDE_DIRS};${${lib}_INCLUDE_DIR}")
-      if(${lib}_LIBRARIES)
+      if(_${lib}_LIBRARIES)
         target_link_libraries("${target}" ${_${lib}_LIBRARIES})
       else()
         target_link_libraries("${target}" ${_${lib}_LIBRARY})